John A. D’Annunzio is President of Paragon Roofing Technology Inc., a construction engineering firm he founded in 1989. He is the editorial director of Building Enclosure and a technical columnist for Roofing Contractor. He has published more than 100 articles and has written four books on building exterior issues. For more information, visit www.paragonroofingtech.com. He can be reached at 248-936-8744.